[cookiemech]

Here's something to investigate: I don't know anything specific about the 4.0 V-6, but when I bought my 2005 Tundra V-8 "work truck" I was disappointed to find that it did not come with factory cruise (though the brochure and website at the time said that it would). I researched the wiring diagram and the truck itself and found that ALL of the wiring was there for factory cruise; it just lacked the switch and harness in the steering wheel. After buying the cruise switch and harness (really just a short wire with connectors) for around $55, I installed it (had to cut a hole in the small plastic cover on the side of the steering wheel that covers the bolt for the airbag; this is where the factory switch goes). Guess what? Took it for a ride, hit the switch, the green "cruise" light illuminated on the dashboard, and the cruise worked just perfect!

Hope there is something available for yours. You will have to find a really good parts guy to help you; lots of them don't know how to order the right parts. My local parts guy (who is very good) told me that it was impossible; that I'd have to buy a new ECU and it was a several thousand dollar proposition. I wound up talking with Jaffarian Volvo-Toyota in Massachusetts.